Machine for correcting splined shafts



' July 20-, 1926.

C. 5. SMITH MACHINE FOR CORRECTING SPLINED SHAFTS 2 Sheets-Sheet Filed August 50, 1924 A TTORNEY5.

INVENTOR. C/z ar/es 618M271? till Patented July 20, 1926.

- STTES CHARLES S. SMITH, F MILWAUKEE, WISCONSIN.

MACHINE FOR CORRECTING SPLINED SHAFTS.

Application filed August 30, 1924. Serial No. 735,221.

My invention relates to a machine for correcting and truing the splines upon shafts, and resides in an arrangement of devices in whichthe, rotating shaft for the abrasive hob and the shaft having the previously formed splines which are to be corrected by the action of the abrasive hob are interconnected so as to be rotated in a predetermined ratio with relation to each other, and in the process of successively grinding in circumferential Zones of the shaft, so that the axially'extending splines may be corrected progressively upon the shaft by grinding away any distortions or inequalities in the material at the sides of the splines and at the bottom of the separating spaces or key-ways.

The shaft which is to be subjected to the corrective action of the abrasive hob, will have produced thereon in any usual manner a plurality of splines equally spaced about and dividing the circumferential line of the shaft by means of alternating spaces or keyways.

The accurate formation of a plurality of splines upon a shaft is a very diflicult operation. After the shaft has been splined and perfected in the usual manner, the heat treatment to which the shaft is then subjected often produces slight distortions in the hardened shaft which require correction in order to restore the alignment and render the splined shaft serviceable, and it is the purpose of this invention to effect such corrections in a very simple, expeditious and accurate manner.

. The improved abrasive hob is provided with helically formed grinding surfaces which are adapted in their continuous action to dress the key-ways or spaces separating the splines. The helical abrading surfaces of the hob will be proportionally spaced to the width of the splines, and the contours of such surfaces to the width and depth of the key-ways.

With each rotation of the abrasive hob, the shaft operated upon by the hob in dressing the splines is partially rotated by means of the interconnection a distance equal to the width of one spline and the key-way at one side thereof, and as the truing up is achieved the shaft operated upon is gradually advanced toward the hob until splines and key-ways of correct alignment throughout their extent have been accurately formed upon the shaft.

of the said shaft.

In order to effect such corrections, there must be an exact synchronization of the rotative movements of the abrasive hob and the shaft being operated upon by the same, and this result is achieved by the interconnection which latter will be hereinafter described.

The novelty of the invention will be pointed out in the appended claims.

In the accompanying drawing I Figure 1 is a View in elevation, looking toward one side of the abrasive hob, and showing the arrangement of the elements of my invention.

Fig. 2 is a plan View of the machine shown in Fig. 1.

Fig. 3 is an end elevation, looking from the right, Fig. 1, with parts shown in vertical section.

Fig. 4f is a view similar to Fig. 3, and showing a modified structure in which the head carrying the shaft of the abrasive hob is provided with an adjusting means, to change the angular relation of the hob to the shaft on which the splines are to be cor rected.

Fig. 5 is horizontal section on the line '55, Fig. 4.

In the drawing, the numeral indicates a stand in which a driven shaft 11 is journaled in bearings 12 and 13; Collars 14: and 15, fixed upon the shaft and in engagement with opposite sides of the journal boxes, will restrain longitudinal movement A spiral gear 15 is formed upon the shaft 11, and an abrasive hob 16 is suitably clamped upon the shaft by collars 17 and 18, the parts being held in position by a nut 19 threaded upon the shaft. A collar 20 may be placed between one end of the spiral gear 15 and the collar 18, to properly space the parts. The peri hery of the abrasive hob 16, is produced wit grinding surfaces formed as a helix, such grinding surfaces comprising a long thread 21, the convolutions of which are spaced as indicated at 22.

A shaft 23 arranged at approximately a right angle with relation to the shaft 11, is journaled in bearings 24 and 25 upon the stand 10. This shaft has out upon its forward end a spiral gear 26, in mesh with the spiral gear 15 upon the shaft 11.

The other end of the shaft 23 is provided with a spiral gear 27, in mesh with a spiral gear 28 of a diameter which is determined by the number of splines which are to be cut upon the shaft. The gear 28 has fixed to one side thereof, a hub 29 having a 01rcumferential groove which is entered by a projection 30 fixed to the'stand 10, so that ongitudinal movement of the said gear 28 is prevented, and a definite position of the spiral gears 27 and 28- maintained at all times. The gear 28 and its hub 29 are mounted upon a sleeve 31 provided with a spline 32. The sleeve 31 is in the form of a chuck and is adapted to receive and firmly hold the splined shaft 33.

In the construction illustrated, I have shown the machine as organized to true six axially extending splines upon the circumference of the shaft 33. The rotation of the abrasive hob 16 and the shaft 33 will therefor be as 1 to 6. A centering fpoint 34 will support the free end of the sha t 33 and prevent vibration duringv the grinding operation.

In actual practice upon shafts having a diameter of about 1% inches, the abrasive hob 16 will have a diameter of about 14 inches, and the angle of the shaft 11 with relation to the line of movement of the shaft 33 will be such that the grinding surfaces of the hob 16 will he as near in parallelism with the axis of the shaft 33 as it is practical to adjust them.

With each revolution of the abrasive hob 16, the s lined shaft 33 is given one-sixth of a revo ution, so that for each six revolutions of the said hob there will be one complete revolution of the shaft 33. The chuck 31 which carries the shaft 33 upon which the splines are being corrected, is advanced in consonance with the grinding operation as each circumferential zone upon the shaft is completed, so that the grinding is effected progressively to the extent desired as the shaft 33 is fed forward.

The thread formation of the helical surface upon abrasive hob 16 determines the width of the splines 35 upon the shaft 33, and the width and height of the surfaces 21 of the abrasive hob determines the width and depth of the key-ways which separate the splines. The rotation. of the shaft 33, upon which the splines are being corrected, is effected positively by means of the gear ing described, so that lateral strain is not imposed upon the helical surfaces of the abrasive hob in effecting such rotation.

In Figs. 4 and 5, I have shown a means whereby the angularity of the shafts 11- and 33 may be adjusted so as to better effect the operations of the abrasive hob, by bringing the surfaces thereof into the desired alignment with the splines which are being corrected upon the shaft 33. The head 10' is swiveled about a vertical shaft 10 mounted to rotate in the stand 10 bevel gears 35 and 36 connecting the shafts 11 and 10 with spiral gears connecting the latter with the shaft 23, as before described. The abrasive hob may therefore be accurately indexed in any desired position with relation to the shaft 33, and clamped in the desired adjusted )osition by means of a clampjing screw 3 7, passing through a slot 38 in the head 10 and threaded into the stand 10. Other means of indexing than that shown may be used.

The exterior lateral surfaces upon the splined shaft may be prepared by other means, but the present invention serves to form the depressed cylindrical surfaces of the shaft disposed between the splines, as well as the radial and axially extending surfaces defining the splines, by removing any distortions and producing splines with true surfaces.

By the employment. of the process disclosed, I have greatly simplified the operations of correcting the splines upon the otherwise finished shafts, and at the same time have produced an automatically operating machine which is absolutely accurate in its work.

Although I have illustrated and described my invention as applied to the correction of splined shafts, it is obvious that the invention is capable of other uses in connection with work of similar nature, that is, in work which presents radial projections like the splines on a shaft and which may have been distorted in heat-treatment, and which as a result of such distortion are in need of .correction.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States, is

1. In a machine for correcting splines upon a shaft, an abrasive hob provided with grinding surfaces in the form of a helix with its axis transverse to that of the shaft, and connections to rotate the shaft in unison with the abrasive hob directly as distinct from by the worm action of the helical grinding surface so that the splines are successively trued upon the shaft.

. 2. In a machine for correcting splines upon a shaft, an abrasive hob having a grinding surface formed as a helix with its axis transverse to that of the shaft, and connections to rotate the shaft in unison With the hob directly as distinct from by the worm action of the helical grinding surface so that the splines are formed in succession circumferentially of the shaft, and meansfor feeding the shaft toward the abrasive hob during the truing of the splines.

3. In a machine for correcting splines upon a shaft, a driven shaft carrying an abrasive hob having a grinding surface formed as a Helix with its axis transverse to that of the shaft, a chuck supporting the nasaara splined shaft to be corrected, and connections between the driven shaft and chuck for rotating the latter in unison with the abrasive hob directly as distinct from by the worm action of the helical grinding surface,

whereby the splines are trued in succession upon the said shaft.

f. In a machine for correcting splines upon a shaft, a driven shaft carrying an abrasive hob having a grinding surface formed as'a helix with its axis transverse to that of the shaft, a gear operatively connected to the driven shaft, a chuck rotated by and slidin in the said gear and carrying the splined s aft to be corrected, whereby the peripheral surfaces of the said shaft are sucessively presented to the abrasive. hob.

5. In a machine for correcting splines upon a shaft, a driven shaft carrying an abrasive hob having a grinding surface formed as a helix with its axis transverse to that of the shaft, a gear operatively connected to the driven shaft, a chuck rotated by the gear in. unison with the driven shaft and carrying the splined shaft to be corrected, whereby the I eripheral surfaces of the shaft are presented in succession to the action of the abrasive hob, and a sliding connection between the gear and the chuck to permit feeding movement of the shaft toward the abrasive hob.

6. In a machine for correcting splines upon a shaft, a driven shaft carrying an abrasive hob having a grinding surface formed a helix with its axis transverse to that of the shaft, a transversely extending shaft geared at one end 0:.- the driven shaft, a chuck-rotating gear as 28 geared to the other end of the transversely extending shaft, and a chuck rotated by the said gear but slidable therein, the said chuck supporting the splined shaft to be corrected, whereby the peripheral surfaces of the shaft to be corrected are presented in succession to the abrasive hob and such shaft is fed forwardly in the grinding operation.

7. In a machine for correcting splines, an abrasive hob provided with a grinding surface in the form of a helix, and a shaft for presenting the work to the hob, the axes of the hob and shaft being arranged transversely with relation to each other, and connections for rotating the shaft directly in synchronisni with the hob, as distinct from rotation by the worm action of the helical grinding surface of the hob, so that the splines upon the Work are successively trued.

8. The process of correcting splines formed upon the circumference of a shaft, which consists in subjecting aisplined and hardened shaft to the action of an abrasive hob having its grin-ding surface formed as a helix with its axis transverse to that of the shaft, and rotating the said shaft directly as distinct from by the worm action of the helical grinding surface to present different surfaces in sucession to the abrasive hob with each rotation of the latter. 9. The process of correcting splines formed'upon the circumference of a shaft, which consists in subjecting a splined and hardened shaft to the action of an abrasive hob having its grinding surface formed as a helix with its axis transverse to that of the shaft, rotating the said shaft directly as distinct from by the worm action of the helical grinding surface to present different surfaces in succession to the abrasive hob with each rotation of the latter, and advancing the shaft toward the hob during the correcting operation to produce axially extending splines of the desired accuracy.

In testimony whereof, I have signed my name at Milwaukee, this 21st day of August,

U. S. SMITH. 

